The MDS (Multi-Displacement System) unit replaces a conventional roller cam follower
with a hydraulically pressurized design consisting of an outer sleeve and piston unit to which a roller follower is attached.
The fuel system that has been developed, named the Integrated Fuel System (IFS), incorporates the unit pump, Compact Pencil Nozzle (CPN), and a roller cam follower. Iris a no-leak off system and it has been qualified at 11,600 psi (800 bar) peak injection pressure.
Stanadyne's unit pump design is a derivative of a current production unit pump with an integral roller cam follower. The unit pump incorporates a number of features to provide speed advance, light load advance and cold advance.
Features retained from the previous design include replaceable induction hardened wet cylinder sleeves, valve seat inserts and valve guides, positive valve rotators and roller cam followers
. Engine life to first overhaul is 500,000 miles.
The revised V8 engine now employs five-valve-per-cylinder technology, and new low-friction valve gear with roller cam followers
Circular cam rings encompass radially disposed pistons with roller cam followers
which ride on the cam rings.